JPH0340477B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar-powered lighting device, and more specifically, it charges a secondary battery using solar power generation means such as a solar cell during the day, and uses the secondary battery as a power source for lighting at night. The present invention relates to a device for performing

The amount of solar radiation is high in the summer and low in the winter, and is not constant throughout the year. Therefore, the electricity that can be obtained from solar power generation means with a certain capacity is not constant, with more in the summer and less in the winter.
The size of the lighting load connected to such solar power generation means should be set to an average value between the maximum amount of power available in summer and the minimum amount of power available in winter, in order to avoid extreme power surpluses and deficiencies. Usually selected.

However, even if you choose an average lighting load, if it rains for a long time, for example, the energy stored in the secondary battery will be depleted, resulting in overdischarge and damage to the secondary battery. At the same time, lighting may become impossible.

This invention was made in view of this point, and protects the secondary battery by monitoring the remaining capacity of the secondary battery and reducing the power consumption of the lighting load when the remaining capacity becomes low. In addition, the lighting system has been improved to ensure illumination ability for at least a predetermined period of time.

Hereinafter, this invention will be explained in detail based on embodiments shown in the drawings. Note that this invention is not limited to this.

1 shown in FIG. 1 is an embodiment of the solar power generation lighting device of the present invention, and is an outdoor lighting device at night in which electric power obtained from a solar cell 2 is stored in a lead storage battery 3, and a fluorescent lamp 4 is lit thereby. be.

The output DC voltage of the lead acid battery 3 is converted into a square wave AC voltage by an inverter circuit 10 mainly consisting of a voltage controlled oscillator 8 and transistors Q ₁ and Q ₂ , and then boosted by a step-up transformer T ₁ . Via fluorescent lamp 4
is applied to

When the fluorescent lamp 4 is in the lighting state, the secondary circuit of the step-up transformer T ₁ exhibits series resonance characteristics,
Maximum load current occurs at a specific frequency. Moving away from that particular frequency, the load current decreases. Therefore, the relationship between the operating frequency of the inverter circuit 10 and the power consumption of the load is as shown in FIG. 2, for example.

The frequency of the inverter circuit 10 is determined by the oscillation frequency of the voltage controlled oscillator 8, and the oscillation frequency of the voltage controlled oscillator 8 is proportional to the control voltage V. This control voltage V is controlled by the output of the comparator 11.

The relationship between the remaining capacity and open circuit voltage of the lead acid battery 3 is
In the case of a 24V sealed lead-acid battery, it is as shown in Figure 3. Then, by detecting the open circuit voltage, the remaining capacity of the lead acid battery 3 can be known. Usually, in a solar power generation lighting device, the discharge rate is small, so the terminal voltage E of the lead-acid battery 3 can be considered to be approximately an open-circuit voltage.
The comparator 11 detects the terminal voltage E of the lead acid battery 3 through resistors 15 and 16, and detects the terminal voltage E of the lead acid battery 3 through resistors 17 and 16.
Compared with the comparison voltage Vr determined by 18,
When the detection voltage is higher than the comparison voltage Vr, the output is set to ground level, and the detection voltage becomes higher than the comparison voltage Vr.
Open the output when it is less than If the output of the comparator 11 is at ground level, the control voltage V becomes a relatively low divided voltage V _L by the resistors 12, 13, and 14;
If the output is open, the control voltage V becomes a relatively high divided voltage V _H by the resistors 12 and 14.
However, as described above, since the oscillation frequency of the voltage controlled oscillator 8, that is, the operating frequency of the inverter circuit 10, is proportional to the control voltage V, when the terminal voltage E of the lead-acid battery 3 is high, the inverter circuit 1
The operating frequency of 0 becomes a relatively low frequency _L , and when the terminal voltage E decreases, it becomes a relatively high frequency _∝H .
By adjusting the resistors 12, 13, and 14, the rated power consumption is achieved at frequency ∝ _L , as shown in Figure 2.
At frequency _∝H , the amount of power can be adjusted so that the power consumption is, for example, 30% of the rated value. Therefore, if the resistors 15, 16, 17, and 18 are further adjusted so that, for example, the output of the comparator 11 is switched when the terminal voltage E is 24.6V, the remaining capacity of the lead-acid battery 3 can be reduced to approximately 35% (25%). It can be controlled so that the power consumption reaches the rated power consumption when it is higher than ℃), and the power consumption is 30% of the rated power consumption when it is lower than that.

From the above, the variable frequency inverter circuit 10 and the secondary circuit of the step-up transformer T ₁ constitute a power adjustment means that adjusts the power supplied to the lighting load, and the comparator circuit 20 adjusts the power supply according to the remaining capacity of the lead-acid battery 3. It can be said that it constitutes a control means for controlling the power adjustment means.

30 is a night lighting circuit. When the illuminance from the sun becomes less than 20x, for example, the resistors 21 and 2
2 than the divided voltage by resistor 23 and Cds2
4 becomes lower, and comparator 25
The output changes from "H" to "L". Then, the long timer circuit 26, which consists of something like the M51845L long time timer IC, will then "enable" the voltage controlled oscillator 8 for about 8 hours.
As a result of sending the signal, the voltage controlled oscillator 8 oscillates and illumination occurs as described above. At other times, the long time timer circuit 26 does not output the "enable" signal, so the voltage controlled oscillator 8 does not oscillate and no illumination is performed.

According to the device 1, when the remaining capacity of the lead-acid battery 3 becomes low, the load is automatically reduced, so that the lead-acid battery is protected. Further, although the lighting becomes darker, it can be illuminated for a longer period of time, so that illumination for a predetermined period of time (e.g., 8 hours) can be ensured.

As understood from the above description, the present invention provides a solar power generation means, a secondary battery charged by the solar power generation means, a lighting load such as a fluorescent lamp, and electric power supplied from the secondary battery to the lighting load. and a control means that detects the remaining capacity of the secondary battery and controls the power adjusting means to reduce the amount of power supplied to the lighting load when the remaining capacity is low. Thereby, a solar power generation lighting device is provided which protects the secondary battery and enables reliable illumination for at least a predetermined period of time.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of one embodiment of the solar power lighting device of the present invention, FIG. 2 is a characteristic diagram showing the relationship between the operating frequency of the inverter circuit and the power consumption of the load in the device shown in FIG. 1, and FIG. FIG. 3 is a characteristic diagram showing the relationship between the remaining capacity and open circuit voltage of a lead-acid battery. 1... Solar power lighting device, 2... Solar cell, 3
... Lead storage battery, 4 ... Fluorescent lamp, 5 ... Chiyoke coil, 6 ... Capacitor, 7 ... Starting circuit, 10 ... Inverter circuit, 20 ... Comparator circuit, 30 ... Night lighting circuit.

Claims (1)

[Claims] 1. A solar power generation means, a secondary battery charged by the solar power generation means, a lighting load such as a fluorescent lamp, a power adjustment means for adjusting the amount of power supplied from the secondary battery to the lighting load, and a power adjustment means for adjusting the amount of power supplied from the secondary battery to the lighting load. control means for detecting the remaining capacity and controlling the power adjusting means to reduce the amount of power supplied to the lighting load when the remaining capacity is low, thereby protecting the secondary battery and at least A solar power lighting device characterized by being able to reliably illuminate for a predetermined period of time.